My guess is the Spotlight concentrates almost entirely on Switch, with 3DS titles being confined to cross-platform releases like Fire Emblem Warriors and Pokemon Stars. 3DS will get lots of love during the Treehouse broadcasts.
So, in terms of 2017 stuff I think we're likely to see in the Spotlight broadcast:
- ARMS, but probably just a quick update on some new stages/characters coming as DLC
- Splatoon 2 launch trailer
- Paid online service/cloud saving/Virtual Console is coming: more information in a future Direct
- Super Mario Odyssey- trailer and some in-depth information, releasing November worldwide
- Fire Emblem Warriors, trailer and release date: September worldwide (Fire Emblem 2018 tease)
- Indie reel: spotlight on select titles (Stardew Valley, Yooka Laylee) (some new exclusive or Switch first indie titles might be 2018)
- Mario + Rabbids Kingdom Battle: releasing in August in North America/Europe/Australasia
-Emphasis on select third party titles for 2017: FIFA, Skyrim, Sonic Forces, Sonic Mania
- Dragon Quest Heroes 1+2 coming to the West (don't know when this would launch)
- Super Smash Bros for Switch: all 3DS/Wii U content, all DLC, plus Inklings, Inkopolis stage, plus Ice Climbers- Either Q4 2017 or Q1 2018
- Xenoblade Chronicles 2 English language trailer- December release worldwide
- Pokemon Stars confirmed for Switch/3DS- launching late October 2017
Things that I think we'll see for 2018:
- Monster Hunter Generations X coming West, spring 2018
- Pikmin 4, spring 2018
- Dragon Quest XI 2018
- Retro Studios game first half 2018
- Animal Crossing summer 2018
Things that will be confined to the Treehouse broadcast will include 3DS titles: Ever Oasis, Hey Pikmin, Miitopia, Monster Hunter Stories and other titles that were confirmed in April. I also expect they'll sneak in one or two 3DS announcements during Treehouse, including a first look at the new Kirby game, as well as a reveal for Mario & Luigi: Superstar Saga 3DS.
Things I would love to see, but don't think we will see
- A new F Zero/Metroid/Kid Icarus/Luigi's Mansion for 2018
- Zelda: Link's Awakening 3D
- More on Project Octopath Traveller
- Star Tropics reboot
- Shin Megami Tensei V
- New No More Heroes (confirmed during the initial Switch reveal, don't think we'll see more till next year)
- In-game Fire Emblem Switch trailer
- Final Fantasy VI remake
Things that have been leaked that we won't see:
- SNES Mini
